As image recording means, an image recorder using an inkjet method (hereinafter referred to as an “inkjet recorder”) has been widely used which ejects ink from inkjet heads to form images.
In such an inkjet recorder, when a recording operation is continuously performed, the ink sprayed from the ejection holes of the inkjet heads adheres and is accumulated on the ink ejection planes and near the ejection holes. This sometimes causes clogging of the ejection holes. When a recording operation is performed under such circumstances, there is a danger that the ink may not be properly ejected, which causes a problem with image recording.
Therefore, the inkjet heads needs appropriate maintenance for proper image recording.
As a method of maintenance, there is a method to wipe an ink ejection plane with a wiping member. A blade made of silicon rubber or the like is generally used as the wiping member.
Recently, with the spread of the application of inkjet recording, inks are developed which can be used for recording on an ink non-absorbable recording medium. Since common inks used for recording on a non-absorbable recording medium is not fixed well, many of such inks for a non-absorbable recording medium contain a lot of resin and have a high viscosity, or have an increased viscosity when cured with external energy such as UV (ultraviolet light) on a recording medium, in order to be well-fixed.
When such an ink adheres around the nozzles on a nozzle plate and the solvent is evaporated, or when the ink which has adhered cures, the viscosity increases. In such a case, it is difficult to wipe the ink off with a blade at the time of maintenance of heads, and in some cases, the ink having increased viscosity may be pushed into the nozzles with the blade.
Patent Literature 1 describes an inkjet recorder wherein the RMV value of ink on a nozzle plane falls within a specific range and wherein the nozzle plane is wiped with a porous blade. The inkjet recorder described in Patent Literature 1 thus leaves no ink remaining to be wiped and prevents the nozzle planes from being damaged. The ink used in the apparatus described in Patent Literature 1, however, is a common water-based ink, and the application of ink for a non-absorbable recording medium is not taken into consideration. When an ink for non-absorbable recording medium adheres to the nozzle planes and sticks thereto fast to some extent, the viscosity of the ink increases. In such a case, the ink cannot be wiped off in the method mentioned above. When the blade is pressed at higher pressure to forcibly remove the ink, the water-repellent layers of the nozzle planes are damaged.
Patent Literature 2 describes pressing a cloth against nozzle planes with a pressing member without moving the cloth on the nozzle planes, which enables the ink to be wiped off without damaging the water-repellent layers of the nozzle planes. Further, Patent Literature 2 describes sucking ink from nozzles with foreign substances to overcome a failing nozzle.
When a prolonged printing causes the ink, which has adhered to the nozzle planes, to cure to some extent, however, the ink cannot be completely removed by merely pressing the cloth against it, and remains as a semisolid substance. When the semisolid substance exists near ink ejection holes, a problem of deformation of the meniscus shape of ink occurs, leading to curving of the ejections.